Anemia is a sign of. Something causing lower red blood cells: blood loss, excessive destruction, or lack of production are possibilities. While the most common is blood loss from bleedig, the source must be found. Anemia may be a first sign of leukemia or lymphoma, but not very likely. Women lose blood menstrually. Oozing blood into GI tract is common. You doctor may work it up or send you to a heamtologist.
Many cause of anemia. Sure, you can have anemia if you have leukemia or lymphoma, however anemia also can be caused by so many other things - like bleeding, iron /vit deficiency hemolysis, etc- not necessarily associated with malignant process. In fact, those other non malignant causes are way more common than leukemia/ lymphoma. If you are concern, talk to your doctor. If your case is complex, see a hematologist.